Train control system



Sept. 19, 1933.

A. E. HUDD TRAIN CONTROL SYSTEM Urignal Filed Aug. 17, 1927 3 Sheets-Sheet 1 HIT-rad Em Hudd Sept. 19, 1933. A E. HUDD TRAIN CONTROL SYSTEM Original Filed Aug. 17 1927 3 Sheets-Sheet 2 Imran n1" Flf Emas Huid Sept. 19, 1933. AE. HUDD 1,927,519

TRAIN CONTROL SYSTEM Original Filed Aug. 1'7, 1927 3 Sheets-Sheet 3 Y is' Patented Sept. 19, 1933 TRAIN CONTROL SYSTEM Alfred Ernest I-ludd, Surbiton, England, assignor, by mesne assignments, to Associated Electric Laboratories, inc., Chicago, Ill., a corporation ci Delaware Application August 17, 1927. Serial No. 213,455

Renewed February 23, 1933 19 Claims. (Cl. 246-63) to the left the main reservoir pressure from the brake valve'passes valve 1 into the passage-way 7, causing the piston to actuate the lever 3..4 In order to positively prevent the inertia of piston 5 from throwing the lever beyond the service position a specially tensioned compression spring 6 is provided. This spring .is encountered by the enlargedportion of the piston slightly before the service position is reached and is cornpressed to its full extent when the lever is moved to service position.

, The lower portion of Fig. 1 discloses what is termed a controller. This device consists in the main, of a casting equipped with an electro pneumatic valve operable by a magnet 2, a light control relay 1l, a Whistle 4, a pneumatic contactor 18 having contacts 19, and a pair of valves and 16 operable by an associated acknowledging or forestalling lever 14. The lever 14 is also provided with an extension which, when the lever is actuated, mechanically locks up the armature of the light control relay 11 in its actuated position. Two auxiliary air reservoirs 28 and 29 shownV immediately below the controller, but connected therewith are provided. The reservoir 28 is for delaying the action of the applicator, while the reservoir 29 controls the action of the pneumatic contactor 13.' VThe interaction of the various devices constituting the foregoing will be gone into in detail hereinafter.

The lower portion of Fig. 2 diagrammatically discloses a plan View of a receiver or magnetic pick-up relay R having the same operating characteristics as the pickup relay in the co-pending application referred to. However, the design has been improved in order to obtain better magnetic circuits, resulting in improved sensitiveness and therefore more reliableV operation is obtained; The relay R comprises four magnetic pickup ele- 95.

The present invention relates in general to train control systems, but is particularly concerned with the development of anauto-manual train stop system oi the intermittent inductive type, and may be considered as a further development of the type of system disclosed in the co-pending Eudd application Serial No. 194,587, led May 27, 1927.

One ol the principle objects of the present invention is to further simpli'y and improve the design of the equipment, making it more reliable and more economical to build and maintain.

Another object is to produce a system which can be readily adapted for use in its simplest form where trac is light and wayside signals are employed, but which may be readily modied to meet conditions where no wayside signalsare used or Where traic is relatively heavy.

@ther objects of the invention. not particularly pointed out will become obvious asthe description of the specic embodiment disclosed proceeds. l A

The invention is disclosed in three sheets of drawings. Fig. 1, when placed immediately above Fig. 2, and taken in conjunction with this ligure diagrarrunatically discloses the mechanism and circuits of the locomotive equipment of the system in its simplest form; w

Fig. discloses the track circuits provided for use in a division inwhich locomotives are equipped with the apparatus wired as in Figs. l and 2.

4 discloses track circuit wiring for divisions in which wayside signals haveY been dispensed with. The locomotives operating Vover such divisions have their equipment wired in the manner diagraininatically illustrated in Fig. 5 or in the manner illustrated in Fig. 6.

Referring now to Figs. l the car apparatus of the specific embodiments of the invention illustrated will be described. At the top of Fig. 1 is a standardlocomotive brake valve l0 equipped with a specially designed head. This head has a hand lever 3 for manually operating the main reservoir pressure in chamber remains above 4% pounds, l'out whenv the pressure falls below this point main reservoir ypressure supplied through head of the valve overcomes the pressure on piston 36. As this piston moves ments 7l-'74 held in the relation shown by nonmagnetic material. Each element has a polepiece for Vinuencing the armature 75, which is normally biased into engagement with eitherpair oi pole-pieces to which it has been actuated by 45 the brake valve in the customary manner. Built 100 in with the however is an applicatoidy con- 9# Simple bm" permanent. magnet NS held 1n place sisi-.ing of a pneumatically operablepiston 5 conby appropriate Clamps- The relay armature iS neues by an associated valve i to automaticalactuated t0 break its upper and make its lower ly actuate the lever 3 into service braking posi- COHtaCS When the lements '7l-74 DESS in l'ldllC- tic-r.. The applicator remains inactive so long as tive ISlaiOll 150 a track-Way element having the l0 energizing the windings on the cores of elements 71 and 74.

Immediately above the receiver R and trackway element is shown a locomotive wheel with a stop detector SD. The stop detector functions to prevent an engineman from releasing an automatically initiated brake application until after the locomotive has come to an absolute stop, in the manner explained in the co-pending application referred to.

While in Figs. 1, 2, 5, and 6 several batteries are shown, it should be understood that actually there is but one battery having its positive pole grounded.

In the embodiment of that portion of the invention illustrated by the track circuits of Fig. 3, the track rails 61 and 62 are divided into blocks by insulated joints 63, two blocks B and C and the adjacent ends of two blocks A and D being shown. The transmission of the desired control influences to the locomotive is brought about by placing a pair of track-way inductor elements approximately six feet apart along the right side of the track-way and at the exit end of each block. The rst element consists of a permanent magnet of the polarity of the one illustrated in` Fig. 2, while the second element encountered is of the electromagnet type and, when energized, is of opposite polarity to that of the permanent magnet. Y

In the disclosure of Fig. 3 it is assumed that way-side signals will be used and these have been conventionally illustrated without attempting to illustrate their Well known control circuits or devices. The electromagnet trackway element TEt at the exit end of block A is energized and de-v energized at the appropriate time under control of a three position polarized track relay 65 through contacts of a track approach relay 66. This latter relay is not necessary, but is desirable Where extreme battery economy is vital. A track battery 64 associated' with the relays 65 and 66 supplies the necessary current for energizing the electromagnet Ta and the approach relay 66. The current for operating the track relay 65 is derived from a track battery 64 associated with the track and approach relays 65 and 66 of the succeeding block which bears the same relation to block B as does the battery 64 to block A. 1

In the illustration under consideration there is a locomotive in block D and a second locomotive is following in block A. The axle of the locomotive in block D shunts the battery supply away from the three position relay 652 causing it to assume its neutral or mid position, as shown. With the relay 652 in this position the track battery 642 has its lower half bridged across the rails of the block C in series with the low resistance approach relay 662 causing the supply of current to the three position track relay 65 to be in the direction appropriate for causing it to shift its armatures to the right. This causes current ow to be supplied to the track relay 65 at the entrance of block B from the upper half of the battery 64', whereby the current ow to the relay 65 is in a direction opposite to 4that supplied to relay 65', and consequently the armatures of the relay 65 are moved to the left, as shown. It will be observed that the element Ta will be energized when the train enters the block A as the train shunts out the track relay at the entrance of the block A and in so doing increases the current ilow through the approach relay 66 causing it to operate. Upon energization rof this relay a circuit for,

the trackway magnet Ta is completed. This circuit extends from the upper half of battery 64, through the lower armature and left contact of relay 65, winding of Ta, and the contacts of relay 66 to the other terminal of the track battery. From the foregoing it will be appreciated that although the receiver relay R is actuated by the magnet T, it is almost immediately restored by the energized electro magnet trackway element T21.

The train upon entering the block B has its equipment operated by the permanent magnet as before, and although the track approach relay 66 is energized as before, the trackway magnet Te has its circuit open at the lower armature of the trackrelay 65 and therefore the relay R on the locomotive is not automatically restored.

Under these circumstances the engineman is given an appropriate warning and should immediately act to simulate the action of an energized track way element by operating lever 14 of Fig. 1. This operation and its effects will be fully described hereinafter.

The trackway elements encountered at the exit of block C are in the same condition as those encountered at the exit of block B.

In the track circuits as illustrated in Fig. 4 it is assumed that all way-side signal equipment has been dispensed with, the locomotives ordinarily operating over this trackway division being equipped with all the necessary signalling devices for keeping the enginemen informed of the track conditions in advance. In this igure the last block of the track is occupied and the polarized relays which are identical to those shown in Fig. 3 are moved to the same relative positions under the same trai'lc conditions. The trackway elements T--T6 and the elements Tai-THG, inclusive, are also in the same relative condition and are influenced like the corresponding trackway elements T---T2 and Te-Ta2 of Fig. 3 by like traillc conditions. In order to avoid unnecessarily complicating the circuits of this gure the approach relays have been omitted, but in order to operate additional signals in the cabs of the locomotives equipped to travel over the divisions in which no wayside signals are provided, an additional electro magnet trackway element is provided between the trackway rails opposite each of the existing trackway lelements Tas-Tas. In order to control the energization and deenergization of these added trackway elements extra track relays such as 'Y6-763 are provided. The wiring arrangement in this division only requires one rail of the trackway to have its block sections insulated from each other and the other railway is used as a continuous conductor. Furthermore, since no wayside signals are used the circuits are arranged for one block overlap control.

Considering now the circuits of Fig. 4 in detail, the auxiliary track relays 76 and 763 are energized. The circuit for the relay '76 extends from the upper half of the trackway battery 644, through the lower armature and left contact of the track relay 654, winding of relay '76, the noninsulated rail 61', and then to the other terminal of the battery. The auxiliary track relay 763 is held energized over a circuit identical with the one traced for relay 76.

With track conditions as described the electromagnet trackway inductors Tfr6 and Tb3 at the exit of block H will be deenergized, Ti6 being included in a non-energized series shunt circuit in cluding the front contact and armature of relay 763, relay 762 and the rail 61', while the element TlD3 has its circuit open at the back contact Vor" relayIG?. The elementsTafand Tb2 at the exit of block G are also deenergized the circuit' of Ta5 being open at thefront contacts of relay .762 and the element Tb2 being included in a non-energized series shunt circuit substantially as traced for T93. The element TM at the exit of block F is deenergized due to its circuit being open at the contacts of relay 76', but the associatedvelement Tbl is energized over a .circuit extending from the upper half of the track battery 64'?, through the lower armature and left contact of relay 654,V armatureand back contact of relay 76', and the Winding of the element Tbll to the other terminal of the battery. At the exit of block El the ele.

ment Ta3 is energized over a circuit including the upper half of battery 643, the lower armature and leftk Contact of relay 653 and the armature and upper contact of relay '76, while the circuit of Tb is open at theback Contact of the lrelay '76.

Operation We will rst assume that the locomotive apparatus is in its normal condition, which is the condition in which it is shown, and that the'locomotive is moving through the block A under clear traine conditions as illustrated in the track-` way circuits shown in Fig. 3. Under these conditions, with the train in block A the electropneumatic valve magnet 2 is energized over a circuit which may be traced as follows: from the grounded side of the vehicle battery on the armature and upper Contact of relay R, the conductor 34 having one branch extending through theA winding of magnet 2 to the ungrounded pole of Vthe vehicle battery, and having a second branch extending through the lamp G to the ungrounded pole of the vehicle battery. The receiver of the locomotive upon encountering the permanent magnet trackway element T, which is very powerful compared to the train carried magnet NS, actuates the armature of the receiver to the opposite position so that the described circuits are broken at the upper contact of relay R and a circuit is completed at the lower contact of this relay for the light relay 11. This circuit extends from the ungrounded pole of the battery through the winding of the light relay 1l, conductor 33, through the lower contact and f armature of the relay R to the grounded side of the battery. Relay 1l operates and at its lower contacts opens a second point Vin the circuit of the green lamp G, and at its upper contact closes a point in a circuit for the purple light P. The release of the electro pneumatic valve 2 as a result of the deenergization'of electromagnet 2 admits main reservoir pressure rfrom reservoir 28 to actuate the whistle 4 as a Warning to the engineman that a trackway inducrtor has been passed. After six feet of travel the receiver encounters the trackway magnet Ta which as ex'- plained in the circuit description, is energized under the conditions assumed and is eiective to restore the armature of the 2receiver Rto its initial-position. Consequently the circuit ofthe light relay 11 is broken, thegreen lamp is againA lighted and the magnet 2 is again energizedy to cut off the air supply from the whistle 4.

Upon encountering the permanent magnet trackway .element T at the exit. of block B the receiverrelay R and light relayll -are again actuated but are not restored totheir initial position by the electro magnet trackway element Tal due to it being deenergized at this'time. Consequently the green lampG remains extinguished,

the vvalve 2"rexnains open and the whistle 4 therefore continues toaudibly warn the engine-- man,for approximately a six second period, determined by the capacity of `reservoir 28, that hehas passed a signal `at caution and must therefore acknowledge by operatinglever 14 or he will be penalized by having the brakes automatically applied.

The operation of the lever 14, suiliciently to unseat the valve l5, permits main reservoir presi sure from the auxiliary reservoir 29 to exhaust to atmosphere througha passageway 17. The sudden rush VAof air impinging upon'the concave end o1 the contact lever 18 is then eiective to close contacts 19. 'This action is only momentary however, for the reason that the reservoir 29 is immediately emptied and can only be replenished through the small oriiice 37. This ar-` rangement prevents the engineman from continuously closing the acknowledging contacts 19 by holding lever 14 operated. As a result ofthe actuation of contacts 19 a circuit for restoring the armature on the receiver relay R into engagement with its upper contact will be completed from the ungrounded pole of theAvehicle battery, through the windings of the receiver relay R, conductor 32, and the contacts 19 to ground. The breaking of the lower contact of the receiver relay R is Without effect at this time for the reason that at the beginning ofthe movement of the acknowledging lever 14 it forced the catch 19 under the hook extension of armature 20, and the armature and hook extension 20is prevented from returning to normal, so that a1- though the circuit of relay ll is broken this point in the circuit of the purple light P remains closed. The closure of the upper contacts of the receiver relay R is effective however as in the previous instances to reenergize the electropneumatic valve magnet 2, thereby cutting off the whistle 4 and permitting normal pressure to be again built up in the reservoirs 28 and 29 and in the chamber 30 via the restricted orifice 35. The condition of the vehicle equipment is now the same as before the receiver relay R passed over the trackway element, except that since the relay l1 is now locked up mechanically, it closes at its upper contact the circuit of the lamp P( instead of that traced to the lampG, toAWarn the engineman that he is operating his locomotive in danger territory.

The purple lainpremains lighted until the armature andlatch extension 2O is unlocked, which can` only take place when the relay 11 is energizedand released independently of the acknowl-` edging lever 14. Since this can only take place at aclear signal it follows that the purple light remains lighted all through the danger zone after the first acknowledgment has been made.. H The condition of the trackway magnets at a signal at stop are identical to those encountered where the signal is at caution. The engineman must therefore acknowledge as in the prior instance.

The contact lever 18 sso weighted that it will not lift at a lower pressure than forti/ pounds in the reservoir 29, which means that if this reservoir is Vbelow that pressure the contacts 19A cannot be closed. Since this is the case, an automatic v,brake application will take place when the pres sure in reservoir 28, chamber 30 and reservoir 29 falls below forty pounds before acknowledging or forestalling action is attemptedbecause, as previously explained, the main reservoir pressure vsupplied'through the brakehead at this stage overcomes the pressure applied to the piston 36 to hold the valve 1 seated, with the result'that air is .permitted to flow through the passageway '7 to the applicator cylinder 12. This causes the piston 5 to move and force the brake lever Binto service position.

Should an automatic brake application occur, as a result of the opening of valve 2, the release of the brakes thereafter cannot be brought about until after the train has been brought to a standstill, because the restricted orices 37 and 35 will not permit pressure to be built up in reservoir 29 while the valve 2 is open. In order to release the brakes the acknowledging lever 14 must be pulled down to its full extent in order to open both the valves 15 and 16. This permits main reservoir pressure to be applied from the pipe 2l to the chamber 13 and through the valve 16 to the pipe 22. The pipe 22 is-connected up with a stop detector SD of the type which does not permit air pressure to be built up in the line 22r unless the train is at a standstill. A stop detector of this type is shown and described in detail in the co-pending Hudd application bearing Serial No. 170,048, led February 2l, 1927. As soon as the main reservoir air pressure rises above sixty pounds the weighted valve 25 is forced off its seat and then, so long as thelever 14 is held down and the locomotive is stationary, air will impinge against the pneumatic contact lever 18 causing its contacts 19 to be closed thereby effecting restoration of the receiver to normal and releasing the brakes in the same manner as when an ordinary acknowledging action was performed.

If the engineman operates the acknowledging lever 14 after an automatic brake application, before the train has stopped no restoring action can be effected because the air pressure in the reservoir 29 will be insuilicient to operate the pneumatic contactor 18. On the other hand if the lever 14 is depressed suniciently to open valve 16, causing the stop detector to operate, suflicient pressure cannot be built up to lift the weighted member 25 and operate the pneumatic contacto-r 18, duejto the escape of air which is caused by the stop detector encountering a moving wheel as set forth in the specication referred to.

InV certain instances it may be desirable to entirely dispense with the wayside signal equipment. When this is done the equipment of Figs. 1 and 2 is amplified by the addition of an additional receiving element R kand a combination of three instead of two lamp signals, as diagrammatically illustrated in Fig. 5. The receiver R is in this case controlled in the same manner as it was in the previous instance, whereas the receiver R' is controlled by an additional electro-magnetic trackway element placed between the rails. A locomotive so equipped is controlled by track equipment as diagrammatically illustrated in Fig. 4.

In the description of the circuits of Fig. 5 the same conditions of the track equipment in Fig. 4 will be assumed to exist'as those assumed to exist in connection with the description of the track circuit of Fig. 3. The operation of the electro-pneumatic valve, acknowledging arrangement, whistle, locking up of the light relay and the working of the stop detector is entirely unchanged. Y

VWhen the locomotive encounters vthe elements T3, Ta3 and Tb at the exity end of the block E the light relay 11 is operated and restored in the usual manner as explainedin connection with similar equipment of the locomotive circuits for operating on the division having circuits as illustrated in Fig. 3.

When the locomotive encounters the'track elements T4, T14 and Tb1 at the exit end of block F the trackway element Tb1 will be energized and although the actual control of equipment will be influenced as it was in the former arrangement when the locomotive encountered track elements T1 and Ta1 at the exit end of block B, the receiver relay R will also be actuated in this case. At its right contact it opens one point in the circuit of the danger lamp R and at its left contact completes a circuit for the added light control relay 50. This relay upon operating, opens a second point in the circuit of the lamp R at its lower armature and at its upper armature and working contact completes a holding circuit for itself and for lighting the lamp Y. This circuit extends from the armature and working contact of the light relay 11, which has been mechanically held operated as a result of the forestalling action of the engineman, through the yellow lightY, hold- V ing Winding of relay 50, working Vcontact and armature of this relay, the restoring winding of the receiver relay R', and the left contact and armature of the receiver relay R to ground, this latter relay having been restored to this position through the usual acknowledging action. Since the'circuit just traced also includes the restoring winding R', this relay also moves its armature back to normal.

Under the foregoing circumstances if the engineer fails to acknowledge, the yellow lamp is not lighted; and the magnet 2 remains deenergizecl because the armature of the receiver relay R Ywill not be restored; and an automatic brake application will result.

After the train has beenbrought to a standstill the brakes may be released in the manner hereinbefore described. Upon restoration of the armature of the relay R to its initial position by the acknowledgingaction the series circuit including the lamp Y, holding winding of relay 50 and restoring Winding of relay R' is completed and the Vehicle may proceed, with the yellow light burning. Y

When the trackway elements are encountered at the exit end of block G the conditions will be the Vsame as those encountered at the exit of block F except that the track element Tb2 will in this instance also be deenergized, and therefore, when the receiver relay R is actuated by its encountering the permanent magnet trackway element T5 the above described circuit, through the left contact of relay R', for holding relay 50 energized and for lighting the caution lamp Y will be broken. The relay 50 upon becoming deenergized breaks a second point in the circuit of the lamp Y and closes a point in the circuit of the lamp R. The engineman, uponacknowledging, again locks up the `light relay 11 and restores the receiver relay R to its initial position to reenergize the electro-pneumaticvalve magnet 2, and since the receiver R' has not been actuated, a circuit is now completed for the danger lamp R, from the groundedarmature and right contact of the receiver relay R', through the varmature and resting contact of the relay 50, lamp R and through the front contact and armature of the light relay 11 to battery. The lamp R willfthereforecon'- tinue to glow until the trackway element T6 at the exit end of the block'isencountered. The track- Way elements at the exit of block H are in the same condition as the trackway elements at the exit of block G and therefore, although the circuits of the electro-magnetic valve magnet 2I and lamp R are again broken when the permanent .magnet element is encountered they are Vagain closed by the acknowledging action.

When the exit of a block is encountered where the trackway elements are in a'condition denoting that the block ahead is clear, the light r'eiay 11 will automatically be energized and then deenergized and the electro-pneumatic valve' magnet 2 will be energized automatically. Since under these circumstances the acknowledging lever does not interfere with the light reday ll, this relay will be restored to its normal deenergized position and the circuit for the lamp G will be again completed indicating that all is clear once more.

It may be that in certain divisions of a system it is desirable to, .as a further precaution, positively limit the speed in the overlap blocks. This may be readily done to the existing system by slight changes i-n the circuits of the locomotive equipment, by adding another relay 51, and by adding a small governor on the axle of the locomotive. These modied circuits and equipment are shown in Fig. y6.

Locomotives equipped and wired as in- Fig. 6 are controlled by trackway equipment as disclosed in Fig. il, and in the same manner as locomotives equipped as in Fig. 5 so far as the operation is concerned when passing elements denoting clear or caution blocks. However, it will be seen that the added relay 51, which is included in the circuit of the lamp G, is energized under clear conditions. This circuit extends from the ungrounded pole of the battery on the armature spring of relay 1l, through its upper contact, the winding of relay 51the lamp G, the windings of relay R', to the left contact and grounded armature of the' relay R. The eiectropneumatic valve magnet 2 is maintained energized'over a circuit including the* governor contacts 52 and the armature and contact of relay 51 in multiple so that the opening of the contacts 52 of the governor will be without effeet. When the caution condition is encountered the circuit through the lamp G and relay 51 is interrupted. The consequent deenergization of relay 51 subjects solenoid' 2 to rcontrol Vby the governor contacts. However, whenv the engineer acknowledges' the relay 50becomes energizedv and a new shunt is accordingly `placed around the governor contacts by'relay 50. On the other hand when the train encounters the other trackway elements in advance of a danger zone as lfor instance the trackway elements at the exit of block GA the relays 50 and 51will both be deenergized and the electro-pneumatic valve is maintained energized solely through the governor contacts 52, and consequently the locomotive must maintain a speed'below that required to open contacts 52 of the governor otherwise the electro-pneumatic valve kmagnet 2 will become deenergized and initiate the brake application. This will cause the whistle to blow in the manner Vherein before described to warnA the engineman that he has exceeded the low speed limit and must immediately reduce the speedy or suffer the penalty of an automatic application of the brakes. Under these circumstances since the-electro-pneumatic valve magnet 2 has its circuit broken at the contacts 52, which are independent of control of the forestalling device, the engineman`r has no other alternative than to irrimediatelyreduce the speed before the six second period has expired or suffer the penalty of having the brakes auto'- mat'ically applied.

The trackway represented in Fig. 4 may be a continuation of the trackway of Fig. 3, but merely represent a diierent division. If locomotives equipped for the division represented by Fig.- 4 are sent over the division represented by Fig. 3 their equipment will function the same as that of the locomotives actually belonging to that division except that a red danger zone cab signal will be displayed instead of a purple. Inversely of course, a locomotive from the division represented by 3,V traveling over the division represented by Fig. fi will only receive the purple danger zone signal when encountering trackway elements Vdesignating caution or stop conditions.

It may occasionally' happen that the locomo- 'tive in stopping is brought to a stop with its receiver R over a permanent magnet induc'tor. This will cause the brakes to be applied after six seconds. In order to release the brakesl it is necessary for the engineman to pull down his acknowledging lever 14 to its full extent and hold it in that position until the stop detectorl operates to bring the receiver R to normal thereby closing the contacts 19. Upon the restoration of the receiver armature the circuit of the electropneumatic valve magnet 2 is again closed and the chamber 28 again becomes recharged back to full pressure which of course takes off the pressure on the applicator piston so thatthe brake valve handle can be easily restored. `After the brake application has been released the locomotive can be moved off' the inductor a's thefull six seconds is allowed before the brakes are again automatically applied after releasing the acknowledging lever.

What is claimed is:

1. In a cab signalling system, `the combination with a vehicle and trackway; of clear,` caution and danger indicating signals inv the vehicle, a pair of magnetic pickup relays 'suspended from the vehicle, permanent and electromagnetic track elements for operating said pickup relays,I and a manually vcontrolled normally open' operating circuit for also operating one of said pick-'uprelays, other relays within the vehicle, and circuit connections within thevehicle controlledby said pickup and other relays for substantially coristantly maintaining' the appropriate signal' ac'- tuated.

2. In a train stop system in which the brakes will automatically be applied `responsive toa predetermined reduction in a brake pipe pressure,

anormally energized electropneumatic valve for preventing such reduction, means for deenergiz'- ing said valve, means responsive to the deener'gi- :tation of said valve for audibly warning an engineman that the reduction has begun', manually controlled means effective if actuated in time to reenergizesaid electropneumatic valve to prevent a brake application occurring but being ineffect'ivevto release the brake application while the vehicle isl in mot-ion, and other manuallyr con'- trolled means co-operating with the first manuallyY controlled means for causing the reenergi'zation of said valve after the vehicle has been brought to a stop irrespective of any delay.

3. In combination with a vehicle andtrackway divided linto blocks, a pair 0fpickup relays on the vehicle, trackway elements for actuating one of said' pickup relays independently oftrafiic conditions and'othertrackway elements for actuating the otherr and restoring the r'st of said relays,

track circuits for energizing a certain trackway three blocks in advance are unoccupied, for energizing only another of the elements when only the rst two blocks in advance are unoccupied, and for opening the circuits of all of the other trackway elements at the exit of the block when either the first or second block in advance is occupied, means in the vehicle for requiring the engineer to acknowledge by performing a definite act at the exit of all blocks excepting those in the first mentioned condition, and means for causing the vehicle to be automatically stopped should the engineer fail to acknowledge.

4. In a braking system, the combination of an engineers brake valve with a manually operable lever for moving said valve, of means for automatically moving said lever to the service braking position without restricting its manual movement to the emergency position, and means comprising a compression spring encountered by said piston near the end of its movement for positively preventing the lever from moving beyond the service position when actuated automatically.

5. In a braking system, the combination of an engineers brake valve with a lever operable both manually and automatically, of means for auto- .matically operating the lever comprising a pneumatically operable piston directly engaging said lever, and flexible means engaged by said piston near the limit ofk its movement for cushioning and definitely limiting the extent of movement of the lever automatically without in any way restricting further manual'movement of the lever.

6. In a cab signal system, a light control relay, a signal having a circuit including normally closed contacts of said relay, a second signal having a circuit including normally open contacts of said relay, other means on the vehicle under control of trackway means to cause the said light control relay, to open the circuit of the first signal and close a point in the circuit of the second signal and manually operable means for causing the actuation of said other means to complete the circuit of said second signal.

7. In an automatic train control system, carcarried apparatus including a receiver relay adapted to be actuated by inductively receivedinfluences from elementslying along thev trackway, car-carried lamp signals and circuits therefor, a car-carried light control relay, a manually controlled device operable to cause the actuation of said relay, and means effective responsive to an actuation of said receiver relay to cause the circuit of one of said signals to be broken, also effective responsive to a second actuation of said relay when caused by said device to complete the circuit of a second one of said signals and effective when caused by inductive action to complete the circuit broken by the rst actuation of said relay.

8. In a train control system, a cab equipped with means for operating a signal and initiating an automatic brake application responsive to the receipt of an inductive impulse transmitted from the trackway, manually controlled pneumatic means operable, within a predetermined time after the actuation of the signal and before the brakes have been applied to cancel the signal and prevent the initiated brake application occurring, and other manually controlled means operable to bring about the operation of said pneumatic means only after thefvehicle has been brought to a standstill.

9. In a cab signalling system, lamps for indicating clear, caution and danger conditions, respectively, a trackway element at the exit of .element at the exit of a block only when at least each block of a trackway for inductively transmitting animpulse to cause any lighted signal to be extinguished and a circuit for the danger indicating lamp to be prepared when a vehicle carrying such signals passes a definite point in a block, a second trackway element subsequently encountered effective to prepare a circuit for said caution lamp in certain instances, and manually operable means for completing the circuit prepared. 10. In a cab signalling system, lamps for indicating clear, caution and danger conditions, respectively, a trackway element at the exit of each block of a trackway for causing any lighted signal to be extinguished and a circuit for the danger indicating lamp to be -prepared when a vehicle carrying such signals passes a definite point in a block, an audible signal also set into operation by said trackway element, and a second trackway element subsequently encountered effective if traiic conditions ahead are favorable to light the clear lamp and to stop the operation of said audible signal and effective at times if the traflic conditions are unfavorable forv preparing a circuit for said caution lamp only.

11. In a train stop system, vehicle equipment including a polarized magnetic pick-up relay, a plurality of cab signals, circuits for said signals including contacts of said magnetic pick-up relay, a winding for operating the armature of said pick-up relay, trackway magnets also for operating the armature of said relay, said armature when operated by a trackway magnet interrupting any formerly completed signal circuit and completing the circuit of a particular one of said signals upon being again operated by a second one of said track-way magnets and manually operable means for causing said magnetic pickup relay to operate and complete the circuit of another of said signals.

12. In a train stop system of the intermittent inductive type, vehicle carried equipment automatically controlled by trackside equipment to initiate an automatic brake application, visual and audible cab signal equipment also controlled by the trackside equipment, means for initiating a brake application and for actuating the audible signal irrespective of theb speed of the vehicle, means for simultaneously changing the condition of the visual signal equipment, means for automatically stopping the actuation of the audible signal, vpreventing the brake application occurring and for again causing a change in the condition of the visual signal equipment to occur and manually controlled means for bringing about the same changes as those caused automatically in the latter instance except that the visual signal equipment will be operated differently.

13. In a cab signalling system, the combination 14.111 a cab signalling system, a set of lamps for 14d indicating traic conditions, magnetic pickup mechanism having contacts and circuits associated therewith including said lamps, trackway magnets for transmitting controlling influences to said mechanism, said mechanism responding to such controlling inuences to interrupt any formerly established lamp circuit, other trackWay elements for causing said mechanism to function and establish a circuit for a particular one of said lamps, and means for alternatively under certain circumstances manually causing the actuation of said mechanism, the circuit completed in the latter operation including another lamp of said set.

15. In a train stop system, lamp signals, a light control relay, a magnetically actuated valve; inductively operable contacts included in circuits including said lamp signals, said light control relay and the magnet of said valve; means for transmitting magnetic impulses to cause the actuation of said contacts to interrupt the circuits including said light control relay, valve magnet and one of said signals and for preparing the circuit of another of said signals; and manually controlled means for causing the inductively operable contacts to complete the prepared circuit and the circuit of said magnet.

16. In combination with a vehicle and trackway divided into blocks, armatures on the vehicle, permanent magnets for normallyholding said armatures in either of two positions, trackway magnets for inductively actuating one of said armatures to its alternative position independently of said traic conditions, other track- Way magnets for actuating the other armature and for restoring said rst armature, track circuits for energizing a certain trackway magnet at the exit of a block only when at least three blocks in advance are unoccupied, for energizing only another of the magnets when only the rst two blocks in advance are unoccupied, and for opening the circuit of all of the other trackway magnets at the exit of the block when either the first or second block in advance is occupied, and

`means in the vehicle controlled by said magnets and armatures for constantly informing the engineer of the character of the block in which the vehicle is traveling.

17. In a train control system, a cab equipped With means for operating a signal and initiating an automatic brake application responsive to the receipt of an inductive impulse transmitted from the trackway, manually controlled pneumatic means operable, Within a predetermined time after the actuation of the signal and before the brakes have been applied, to cancel the signal and prevent the initiated brake application occuring, and other manually controlled means controlled from within the cab to bring about the operation oi" said pneumatic means only after the vehicle has been brought to a standstill.

18. In a train control system, a receiver relay operable independently of and also in accordance With traflic conditions, a light control relay for controlling signals in accordance with traic conditions as indicated by actuations of said receiver relay, and a manually controlled pneumatic contactor for varying the signal control effect caused by an actuation of said receiver relay.

19. In a cab signal system, lamp signals, a relay having a pair of contacts included in a circuit including one of said signals and having another pair of contacts included in a circuit including another of said signals, a second relay having a pair of contacts included in a circuit common to said lamp signals, means for actuating said second relay to thereby break the common circuit for said signals and other means for then causing the rst and second relays to move their contacts and complete the circuit of the second mentioned of said signals.

ALFRED E. HUDD. 

